    [Patent document 1] JP-2006-199110 A (US2007/0257783 A1)    [Patent document 2] JP-H10-201001 A
At the time of traveling of an electric vehicle or at the time of motor drive traveling of a hybrid vehicle, it may be desired that a person outside of the vehicle can recognize the presence of the vehicle approaching. To that end, an audio speaker is installed in the subject vehicle to thereby produce a notice sound outside of the vehicle such as a false engine sound and a false running sound for teaching the presence of the vehicle.
However, since the notice sound outputted from the audio speaker is diffused around, it may be heard by a pedestrian (for example, a pedestrian who is present in the back of the vehicle that advances forward) who is not present in a dangerous position, or a person who is in a vehicle compartment. Thus, the sense of discomfort may be given to the people other than a pedestrian who is present in the dangerous position.
The applicant filed Japanese Patent Application No. 2009-58456 (JP-2010-208557 A) proposing a vehicle presence notification apparatus which generates a notice sound by emitting an ultrasonic wave in the air based on an ultrasonic signal modulated according to an audible sound. The notice sound outputted by the vehicle presence notification apparatus has a significant directionality. Thus, the notice sound for teaching a presence of a vehicle approaching can be designed to be conveyed to a pedestrian or the like who needs to be notified of the presence of a danger. Thereby, the sense of discomfort due to the notice sound can be reduced for a pedestrian, who is not present in a dangerous place or a person who is inside of a vehicle compartment.
Even at the time of traveling of an electric vehicle or even at the time of motor drive traveling of a hybrid vehicle, a wind roar or a road surface sound occurs when a vehicle velocity becomes greater than a predetermined value. Even without generating a notice sound, a pedestrians can thus recognize the presence of the vehicle.
That is, the generation of the notice sound in the vehicle presence notification apparatus is only necessary for just the case where the vehicle runs at such a low vehicle velocity hardly producing a running sound. Accordingly, when the vehicle velocity is great or fast, the vehicle presence notification apparatus mounted in the vehicle is not utilized. This poses a disadvantage. In addition, from the request of reducing the number of in-vehicle components, it is desirable that the vehicle presence notification apparatus provides another function other than the generation of the notice sound.